A sum of money doubles in 4 years at a certain rate of compound interest. In how many years will it become 8 times?
If $\log_2 x + \log_4 x = 5$, what is the value of $x$?
A boat travels 36 km downstream in 3 hours and 24 km upstream in 3 hours. What is the speed of the boat in still water?
If $x^2 - 5x + 6 = 0$, what is the value of $x^3 - 3x^2 + 2x$?
A shop sells two types of pens at Rs. 10 and Rs. 15 each. If 50 pens are sold for Rs. 650, how many pens of Rs. 10 were sold?
The cost price of an article is Rs. 200. It is sold at a 10% discount on the marked price, yielding a 25% profit. What is the marked price?
If $a, b, c$ are in geometric progression and $a + b + c = 21$, $abc = 216$, what is the value of $b$?
A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less. What is the speed of the train?
If the area of a square is 64 cm², what is the length of its diagonal?
A sum of Rs. 1000 is divided among A, B, and C in the ratio 2:3:5. How much does C get?
If $x^2 + y^2 = 25$ and $xy = 12$, what is the value of $x + y$?
A shopkeeper marks up an article by 25% and then offers a 20% discount. What is the net profit percentage?
The number of ways to arrange 5 distinct books on a shelf is: